linux-kernel - [RFC PATCH 3/4] x86: disable llvm-cov instrumentation

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Message-ID: <20251014232639.673260-4-sashal@kernel.org>
Date: Tue, 14 Oct 2025 19:26:38 -0400
From: Sasha Levin <sashal@...nel.org>
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Subject: [RFC PATCH 3/4] x86: disable llvm-cov instrumentation

From: Wentao Zhang <wentaoz5@...inois.edu>

Disable instrumentation for arch/x86/crypto/curve25519-x86_64.c. Otherwise
compilation would fail with "error: inline assembly requires more registers
than available".

Similar behavior was reported with gcov as well. See c390c452ebeb ("crypto:
x86/curve25519 - disable gcov").

Signed-off-by: Wentao Zhang <wentaoz5@...inois.edu>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/crypto/Makefile | 1 +
 lib/crypto/Makefile      | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/crypto/Makefile b/arch/x86/crypto/Makefile
index 2d30d5d361458..9fac64c39766f 100644
--- a/arch/x86/crypto/Makefile
+++ b/arch/x86/crypto/Makefile
@@ -77,3 +77,4 @@ aria-aesni-avx2-x86_64-y := aria-aesni-avx2-asm_64.o aria_aesni_avx2_glue.o
 
 obj-$(CONFIG_CRYPTO_ARIA_GFNI_AVX512_X86_64) += aria-gfni-avx512-x86_64.o
 aria-gfni-avx512-x86_64-y := aria-gfni-avx512-asm_64.o aria_gfni_avx512_glue.o
+
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index bded351aeacef..9a8040ea7b626 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -81,8 +81,9 @@ libchacha20poly1305-$(CONFIG_CRYPTO_SELFTESTS)	+= chacha20poly1305-selftest.o
 obj-$(CONFIG_CRYPTO_LIB_CURVE25519) += libcurve25519.o
 libcurve25519-y := curve25519.o
 
-# Disable GCOV in odd or sensitive code
+# Disable GCOV and llvm-cov in odd or sensitive code
 GCOV_PROFILE_curve25519.o := n
+LLVM_COV_PROFILE_curve25519-x86_64.o := n
 
 ifeq ($(CONFIG_ARCH_SUPPORTS_INT128),y)
 libcurve25519-$(CONFIG_CRYPTO_LIB_CURVE25519_GENERIC) += curve25519-hacl64.o
-- 
2.51.0